The present invention relates to a method of operating a secondary battery to recondition the battery, in which the battery repeats charge and discharge cycles, and more particularly a method of operating a secondary battery to recondition the battery in which zinc (Zn) is used as the negative electrode active material.
Examples of the secondary battery using zinc (Zn) as the negative electrode active material include a zinc-bromine, zinc-chlorin, nickel-zinc, air-zinc battery, etc. The operation of this type of secondary battery to recondition the battery is effected by a complete discharge method with intent to completely dissolve the zinc on the negative electrode for the purpose of increasing the charge and discharge battery life. With this complete discharge operation, the secondary battery is discharged until the battery voltage and the load current are substantially reduced to zero.
However, even if the complete discharge operation is performed, the zinc on the negative electrode is not completely dissolved and some of the zinc remains on the negative electrode. As a result, when the charge of the next cycle is effected, the zinc is further electrodeposited on the remaining zinc on the negative electrode. Depending on the conditions, this electrodeposition of the zinc takes the form of an abnormal electroposition which is called as a dendrite. Thus, if the abnormal electrodeposition causes the zinc to extend to the positive electrode, this gives rise to a problem of battery short-circuit. Moreover, where the battery has a large size and a large capacity, the above-mentioned complete discharge operation consumes a large amount of electric power wastefully.